Weighing apparatus has previously been proposed comprising a weighing table secured to a support frame by way of load beams which produce electrical output signals indicative of the weight resting on the weighing table. An example of such a weighing apparatus is disclosed in copending patent application No. GB 0625240.7, where the weighing apparatus is built into the bale chute of an agricultural baler to weigh bales before they are discharged.
A perspective view of a known load beam is shown in FIG. 1. The load beam is constructed as a rod 12 of rectangular or square cross-section with holes 14 near its ends for receiving securing bolts.
FIG. 2 shows the load beam 10 of FIG. 1 when used in mounting a weighing table 16 on a support frame 18. On one side, the load beam 10 is connected by a securing bolt 20 to the weighing table 16 and on the other end it is connected by two bolts 22 to the support frame 18. A connection block 23 is placed between the load beam 10 and the support frame 18. This block 23 is used to level the load beam 10 to the horizontal in the weighing position, since the support frame is connected to a sloping chassis of the baler.
As an alternative, the block 23 can be omitted and the load beam 10 connected directly to the support frame 18. In this case, extra compensation is needed by software.
When a weight is supported on the table 16, the shearing force on the load beam 10 is measured by a sensor 24 which produces an electrical output signal indicative of the force acting down on the weighing table 16.
Conventionally, three or more load beams are used to mount a weighing table on a support frame but in the bale chute application mentioned above, it is proposed to use only two such load beams, one on each side of the bale chute. Because of the heavy weight of the bales and the fact that their centre of gravity does not at all times act directly down on the axis of the bolt 20, there is a moment tending to bend the bolt 20 in the manner shown in FIG. 3.
It would be highly desirable to enable the connection between the weighing table and the load beam of a weighing apparatus to withstand a large bending moment without damage to the securing bolt passing through the load beam.